Paint in the United States is normally supplied for the home use retail market in ½ pint, pint, quart and 1-gallon cylindrical metal containers formed of metal with removable tops. The removable tops of 1-gallon and smaller cans have a convoluted rim that is press fit into a matching rim, to form a tight seal. Often paint poured from these cans into other containers (smaller cans, paint roller pans, etc.) for more efficient use, flows over and into the convoluted edge which inevitably contaminates the seating area and runs down the side of the can and often on to work area forming a paint ring where the can sits. When a paintbrush is dipped into the can and then drug across the curved rim area, paint also gets into the sealing area. Upon resealing the can, this contamination can result in a less than airtight seal and the remaining paint may dry out during storage. Due to the configuration of the top convoluted edge of the can being located radially inward from the periphery, it is difficult to get all of the paint poured out causing waste and leaving residual material creating disposal issues.
Paint is also sold in larger containers such as a standard 5-gallon metal or plastic container. The lids of these containers are often provided with a small removable seal cap used for adding color or other additives. Paint can be poured from the 5-gallon can through the seal cap or by removing the complete lid. This contaminates with paint the top area around the seal cap and usually the side of the can. Paint can also be removed from the 5-gallon cans with power suction lines. Insertion of the suction lines and strainers often requires the complete top of a 5-gallon can to be removed which breaks the seal. Some 5-gallon cans brought on the market recently are using slightly larger seal caps.
Unused paint is usually stored in its original can. Repeated opening and closing of the top gradually reduces the sealing capability allowing air and moisture to enter or paint to seep out when can is upset. Each repeated opening becomes more difficult to affect a tight seal. The surfaces of the 1-gallon and smaller cans that are not pre-coated easily rust when exposed to humid conditions. Since the convoluted seal is not very tight due to paint and rust contamination, moisture gets inside the can which causes rusting and contamination of the remaining good paint unless rust prevention interior coatings are used. This rusting in the rim area also makes it difficult to subsequently remove the top, and after only a few openings, pliers are usually required. Liquid paint left in the convoluted seal as a result of pouring inevitably splatters when the top is pressed or hammered into place.
The cylindrical shape of any can of any size does not provide for economical shipping and storage of paint. One-gallon cans are usually shipped in cardboard boxes, 4 to a box. Up to about 27% of the available shipping space is not used. One and 5-gallon cans are stored and displayed in stores and warehouses in stacked columns with up to about 27% wasted space. Many adapters have been devised for attachment to the top of paint cans, but these adapters are typically messy to use. They have had only limited success in solving the problems discussed above.
A relative new plastic square paint can, introduced by Dutch Boy®, has features that include a pliable plastic holding bail, a handle cast into the side of the can, and a large, deep closure cap with two external lugs for assistance in unscrewing. An internal formed lip at the top of the can provides a pouring channel for the contents and a place to wipe off a paintbrush without contaminating the closure. The closure cap fits over this pouring channel when screwed onto the can body. The bottom of the plastic can has a slight indentation the shape of the top of the closure cap to enable stacking of cans. The can body is made of two parts, a main body and a snap-in ring that forms the pouring channel. The Dutch Boy® plastic can does not permit complete emptying of the contents. Paint gets between the two body parts, the pouring action is not free of messy paint on the side of the can or from drips off of the top of the snap-in pour channel. Stacking is susceptible to easily sliding off the lower unit. The formed handle in the main body takes up content space thereby increasing the height of the can to compensate and provide for a full gallon. The formed handle in the corner of the can turns out to be difficult to use in holding a full can while using a brush for painting. U.S. Pat. No. 5,855,304 issued to the present Applicants described a square plastic paint can with a large screw cap and a small swivel pour valve. Water coolers with swivel pour valves are commercially available, and many square cans made of both plastic and metal are used commercially for the containment of a great variety of products.
What is needed is an improved can for paint and other fluids